Abstract:
:Disruption of the integrity of the plasma membrane by amyloidogenic proteins is linked to the pathogenesis of a number of common age-related diseases. Although accumulating evidence suggests that adverse environmental stressors such as unbalanced levels of metal ions may trigger amyloid-mediated membrane damage, many features of the molecular mechanisms underlying these events are unknown. Using human islet amyloid polypeptide (hIAPP, aka amylin), an amyloidogenic peptide associated with β-cell death in type 2 diabetes, we demonstrate that the presence of Ca(2+) ions inhibits membrane damage occurring immediately after the interaction of freshly dissolved hIAPP with the membrane, but significantly enhances fiber-dependent membrane disruption. In particular, dye leakage, quartz crystal microbalance, atomic force microscopy, and NMR experiments show that Ca(2+) ions promote a shallow membrane insertion of hIAPP, which leads to the removal of lipids from the bilayer through a detergent-like mechanism triggered by fiber growth. Because both types of membrane-damage mechanisms are common to amyloid toxicity by most amyloidogenic proteins, it is likely that unregulated ion homeostasis, amyloid aggregation, and membrane disruption are all parts of a self-perpetuating cycle that fuels amyloid cytotoxicity.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Sciacca MF,Milardi D,Messina GM,Marletta G,Brender JR,Ramamoorthy A,La Rosa Cdoi
10.1016/j.bpj.2012.11.3811subject
Has Abstractpub_date
2013-01-08 00:00:00pages
173-84issue
1eissn
0006-3495issn
1542-0086pii
S0006-3495(12)05058-8journal_volume
104pub_type
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